


My Red Valentine

by LazyRainDancer



Category: Undertale (Video Game)
Genre: Ain't that what the holiday's for? ;), Alternate Universe - Underfell, Fluff, Happy Valentine's Day!, Hope y'all enjoy both presents!, Hope you'll still be able to enjoy it XD, It's like 90 percent making out and 10 percent plot lol, Just lots of making out with your skeleton boyfriend, No Smut, Other, Reader Is Not Chara, Reader Is Not Frisk, Reader is gender neutral, Reader-Insert, There's honestly not a lot of plot in this, This is my other Valentine's Day oneshot
Language: English
Status: Completed
Published: 2018-02-14
Updated: 2018-02-14
Packaged: 2019-03-18 20:10:32
Rating: Not Rated
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,138
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13688940
Author URL: https://archiveofourown.org/users/LazyRainDancer/pseuds/LazyRainDancer
Summary: Your plans to spend Valentine's Day with your boyfriend had to unfortunately be cancelled after you received a call the week before Valentine's from your cousin who asked you to help take care of your sick aunt until someone else could arrive and take over. As a result, you haven't seen Sans in a week, and you're really starting to miss him since you've never been away from him for this long. Your luck turns around for the better when your cousin happens to arrive on Valentine's Day to take over for you. You immediately head for home in hopes that you can still spend some of the holiday with your boyfriend.Once you get home, you quickly find out that Sans has been missing you just as much as you have been missing him. Now that you're back in his arms, he doesn't plan on letting go anytime soon.





	My Red Valentine

**Author's Note:**

> For those of you who don't know, I wrote this oneshot as a result of a poll I held on my Tumblr. I wanted to write something for my readers for Valentine's Day, so I asked my followers/readers to vote on which skeleton they wanted to be their Valentine. Underfell Sans tied for first with Gaster Papyrus, so I decided to write separate oneshots for the two. This is part 2 of my Valentine's Day present. I've already posted the G Pap/Reader fic if you'd like to check it out ^^
> 
> Also, this takes place in the world of Underfell so Red is referred to as Sans.
> 
> I hope you enjoy the fic! :)

Valentine’s Day has finally arrived. You have been looking forward to this day since February began. This will be your first year to spend the holiday with your boyfriend, Sans. Even though the skeleton is extremely lazy, you were still excited to see what he had planned for the day.

Unfortunately, that excitement quickly went down the drain when you got a call from your cousin the week before Valentine’s Day. Apparently, your aunt had caught a bad case of the flu and needed someone to take care of her.

Her husband passed away a few years ago, and her children have all graduated and started their own careers. So, your aunt is currently living on her own. None of your cousins live closeby, and no one can come right away to help their mother because of their busy schedules. 

Out of everyone in the family, you’re the one who lives the closest to the older woman, and by close, you mean you’re within a three hour radius. As a result, your cousin called and asked you to look after the poor, sick woman for the week until one of her children could arrive to take over for you.

This particular aunt is one you’ve always been close to since you were a child. Despite having several children of her own who constantly kept her busy, she never missed a single birthday of yours. Every year, you would receive a card and a call from her without fail. She would check on your often while you were in college to see how your classes were going and if you were doing alright living on campus. You lost count of how many goodies she sent you while you lived in the dorms. Your aunt is literally one of the kindest women you’ve ever met.

So, while you were really looking forward to spending Valentine’s Day with your boyfriend, there was no way that you could turn down helping your sweet aunt. Thankfully, Sans was understanding and didn’t complain about you having to leave although you could tell that he was secretly disappointed. 

That’s why you’re not currently with your boyfriend on the most romantic holiday of the year. Instead, you’re in your car driving back from your aunt’s house. 

One of your cousins had arrived around the middle of the afternoon to relieve you of your duties. While you had offered to stay longer, your aunt shooed you off and told you to book it home so that you could spend the rest of the holiday with your boyfriend.

Which is why you’re now driving above the speed limit so you can get home as soon as possible. You might not get to have a romantic date for Valentine’s, but at this point, you don’t really care. This is the longest you’ve spent away from Sans since you started dating him two months ago. Even though you know that a week really isn’t that long, that doesn’t change the fact that you’ve been missing him like crazy. You wonder if he’s feeling the same way or if you’re just being over-dramatic.

Rather than call Sans to let him know you’re coming home, you decided to keep your sudden return a surprise, so he doesn’t know that you’re on your way back. Right before you started driving, you texted him to let him know that you’d be busy for the next couple of hours and that you’d call him as soon as you finished. Of course, he doesn’t know that you’ll be busy driving not taking care of your aunt.

It’s evening by the time you arrive at your house. Relieved to finally get out of your car, you quickly exit the vehicle but make sure to close the door softly. You don’t want to make too much noise to alert Sans of your return.

Since you had asked him to house-sit for you while you were gone, you figure he should be inside. Although he still lives with his brother, Sans spends more time at your house than his own, so although you doubt he actually did anything to cleanup while you were gone, you figured you’d ask him to look over the place so that he’d have an excuse to come here if he wanted to.

Once you’re at the front door, you bring out your house key and try to unlock the door as quietly as possible. Considering how perceptive your boyfriend is, you’re honestly not expecting to be successful in surprising him, but you wanted to at least try.

After you get inside, you notice how most of the lights are off downstairs which is making it difficult for you to clearly see anything. Well, since the TV’s not on, that means Sans isn’t in the living room. Is he already asleep upstairs?

A frown appears on your face. Looks like you might have come too late. If he’s already asleep, then there’s nothing you can do. You don’t really want to wake him up since he often goes through these spells where he doesn’t sleep very well. He confessed once that he always sleeps better when he stays over with you, so you’re worried that your absence might have negatively affected his sleep schedule.

Just as you turn to head for the stairs, Sans suddenly appears in front of you via teleport. The only reason you’re able to notice his approach is because of his bright, red eye-lights which widen at the sight of you. Considering his surprise, rather than think you had come home early, he must’ve thought someone else had entered and was trespassing into your home.

You grin sheepishly at him. “Uhh..Surprise?”

In a flash, you’re swept into his arms, and his mouth is pressed roughly against yours. You gasp in surprise but immediately melt into his touch, wrapping your arms around his neck and pressing yourself closer to him.

A possessive growl reverberates in his chest which sends a pleasant shiver down your spine. His sharp teeth graze across your bottom lip as he deepens the kiss. The more he presses into the kiss, the more charged his magic becomes which causes your lips to tingle in the most delightful way. 

Taking advantage of your parted lips, his tongue quickly slides inside your mouth and entwines with yours. A pleased moan escapes your lips at the contact as you attempt to pull him closer.

As expected, his kiss tastes faintly like mustard; they always do since he consumes so much of it. To your surprise, you can also taste whiskey as his tongue wraps around yours which makes you believe he’s been to Grillby’s recently. While the combined flavor is unusual, you can’t say you hate it since his kisses always leave you craving for more. 

You feel one of his hands rise under your shirt to rest at the small of your back while the other cups the back of your head. In response, you dig your fingers into the vertebrae of his neck which makes him groan into the kiss.

Right as you begin to feel your lungs burn from lack of air, Sans pulls back and ends the kiss. Then, you feel yourself being shifted as the skeleton teleports the two of you. In a blink, you find yourself lying on your side in your bed with Sans’ arms still wrapped tightly around you.

Sans smirks as he watches you try to regain your breath. “now, that’s what i call a surprise. didn’t expect to see ya today, sweetheart. how long have ya been plannin’ this?”

A faint red blush covers his cheekbones when you reach up to kiss his cheek. “My cousin showed up a couple of hours ago. They told me I was free to go. I drove as fast as I could so I could come home and surprise my handsome boyfriend whom I’ve been missing a lot.”

His blush darkens which makes you grin in amusement. While he always tries to be the tough, bad boy, there’s no changing the fact that he’s weak to sincere compliments. It’s surprisingly easy to make your boyfriend blush which you find adorable.

You bring your arms to wrap around his chest in a hug as you affectionately nuzzle his neck. His breath hitches when you plant a kiss on one of his vertebrae. “I know it hasn’t been that long since I last saw you, but I really did miss you, Sans. I hope that doesn’t make me sound too clingy.”

Sans tightens his grip on you and kisses your neck which makes you involuntarily shiver. “nah. it’s the same for me. i wasn’t plannin’ on admittin’ it, but i can’t really stay quiet after hearin’ you say it, sweetheart. i’m real glad to have you back. havin’ to go a whole week without kissin’ you was the worst.”

Your heart warms at his admission. Looks like this last week was rough on both of you. Before you can respond, you feel Sans grin against your skin. “but, i found things more bearable once i realized that this meant you’d have to pay me back for everythin’ i’ve missed out on once you got back. you’ve got quite the tab now, sweetheart.”

A giggle escapes your lips. “So, I have a kiss tab now? How many do I owe?”

The skeleton pulls away so he can meet your eyes. There’s a mischievous glint in his sockets as he smirks. “countin’ is too much work. i just figured i’d let you kiss me ‘til i’m satisfied. since you made me wait so long, i think that’s fair, don’t you?”

Amused, you raise your hands to gently cup his cheeks. You lean closer and begin to leave a trail of kisses across his face, making sure that not a single inch goes uncovered.

With each kiss, his blush grows progressively darker, making his face light up like a red neon sign. Finally, your lips come to a stop right above his mouth, the only place left to be kissed.

Your breath fans out across his teeth which makes him tighten his grip in response. His eyes are hooded as he stares at you with blatant desire. You gently stroke his cheekbones with your thumbs as your eyes fall half-mast. “But, Sans, if the condition is to keep kissing you until you’re satisfied, then it’s up to you to decide when you’ve had enough. If you don’t tell me when to stop, I’ll just keep kissing you, and it’ll never end. Are you prepared for that?”

A shiver travels down your spine when he pins you with his now smoldering gaze. The arm around your waist tugs you closer to him while his other hand cups the back of your head. His seductive smirk grows when he notices you shiver. “sweetheart, that was my plan from the start. i don’t plan on lettin’ you go anywhere for awhile. now that you’re back, you’re all mine. i hope you’re ready.”

With that, his mouth captures your lips in a heated kiss. Sans wastes no time in using his sharp fangs to part your lips. Within seconds, his tongue enters and begins to explore every inch of your mouth, leaving an electric trail in his wake. In no time, his tongue is wrapped around yours, stroking and caressing with a hunger you haven’t seen him display in a while.

His fingers thread into your hair and dig deep as he tilts your head to deepen the kiss. Sans uses his other hand on your back to pull you until you’re pressed flush against him, leaving no space between your bodies. The way he moves his tongue is almost sinful; you can’t help but moan in pleasure as he practically ravages your mouth.

When he pulls back, Sans brings his mouth to your neck and leaves a trail of kisses there which makes you shiver. In response, you tilt your head to give him more access to your skin which he gladly takes advantage of. 

You clutch him tighter when his teeth mercilessly scrape across your skin. At one point, his fangs dig deeper on a particularly sensitive spot which makes you whimper. Immediately, his tongue comes out and begins to stroke that area with a tenderness that takes your breath away. 

Not wanting to be the only one on the receiving end, you leave one arm wrapped around his neck while you bring the other to move under his shirt. He groans into your neck when your hand starts to caress his more sensitive ribs.

While your nails sensually scrape across his ribs, your other hand digs deeper in the vertebrae of his neck. Sans shudders under your touch which makes you smile. His breath then hitches when you start planting chaste kisses under his chin and continue downwards until you reach the collar of his sweater.

Dimly, you wonder where his jacket his; Sans wasn’t wearing it when he came downstairs. You kinda miss the soft fur which you usually rub your face against when he pulls you this close.

His sweater begins to ride up revealing his rib cage as your hand continues to move upwards to stroke his upper ribs. As soon as his sternum comes into view, you waste no time in leaning down to leave a trail of kisses across the long bone. Your lips linger longer with each kiss which elicits a moan from the skeleton.

When you finish, you let your mouth hover above his sternum for a few seconds and bask in the way his body shivers as your hot breath hits the exposed bone. After leaving another chaste kiss there, you pull away so that your eyes can meet his heated gaze.

Immediately, Sans yanks your head closer and crashes his mouth against yours. Grinning mischievously, you dig your fingers deeper into the vertebrae of his neck while simultaneously scraping your nails across one of his more sensitive ribs.

The response is instantaneous. Sans releases a deep moan and clutches you impossibly closer. You take advantage of the opening and slide your tongue into his mouth before he can do it to yours.

You want to laugh when you hear him growl at your actions. Instead, your grin just grows as you deepen the kiss by plunging your tongue further inside the cavern of his mouth.

Over the time you’ve been dating Sans, you’ve quickly learned after several make-out sessions which particular areas to stroke to get a reaction out of him. Normally, he’s the one to dominate the kisses, so you always try to make the most of it whenever you get to lead.

As a result, you make sure to caress every one of his sweet spots with the utmost tenderness. One of your goals whenever you kiss him is to always show him how much you treasure him. The skeleton doesn’t exactly have the highest self-esteem--not that he would admit it thanks to his pride. So, you’ve made it your job to show Sans how much you adore him every chance you get. To you, he’s the most important person in your life; no one else can compare.

Sans clutches you tighter as if reading your thoughts. His hand on your back moves under your shirt and starts stroking your skin repeatedly with a gentleness that simultaneously surprises you and warms your heart.

When you finally pull away, you open your eyes half-mast and see his equally hooded sockets looking back at you with a tenderness you only see when the two of you are alone. It’s a special sight for you and you alone.

A happy sigh escapes your lips when he moves his hand to cup your cheek and lightly stroke your skin. His expression softens when you immediately lean into his touch.

Sans leans forward to rest his forehead against yours. Your breaths intermingle as the two of you lovingly stare at each other. 

The corners of his mouth turn upwards as he softly grins. “i don’t know what i did to deserve someone as amazin’ as you, sweetheart, but i’m glad i did. i’m not really interested in most human holidays, but i’ll admit that what we have is definitely worth celebratin’. i know on valentine’s you’re supposed to go out and do somethin’ romantic, but honestly, all i want is to have ya in my arms, sappy as that sounds. i don’t have any special gifts to give like some guys, but i can for damn sure make you feel like the most loved person on the planet. i’ll give you anythin’ you want, sweetheart, just say the word.”

With a smile, you leave a chaste kiss on his teeth and then affectionately nuzzle his cheek. “But, I’ve already got everything I want, silly. I have you. What more could I ask for when I’ve already got the best gift ever?”

His cheekbones turn a dark red at your words. Sans releases a breathy chuckle. “damn. when it comes to sweet talkin’, you always put a good fight, sweetheart. you know just what to say to leave me _breathless_.” 

You giggle as you give his brightly glowing cheek a kiss. “Of course, if I’m gonna stand a chance against the biggest sweet-talker in town, I need to have some skills of my own.”

Sans nips at your earlobe with one of his fangs which makes you involuntarily gasp. You tremble at the way he sensually runs his hot tongue along the shell of your ear. 

A large smirk forms on his face when he pulls away and sees your red cheeks. “while you’re definitely gettin’ better with your words, i don’t plan on losin’ when it comes to providin’ physical pleasure. you won’t be beatin’ me in that area anytime soon, sweetheart.”

In response, you purposefully dig your fingers into one of his lower vertebrae and caress his sternum with your other hand. While Sans manages to contain his groan, he’s not able to stop the blush that lights up his face. 

Wearing a matching smirk, you plant a few kisses under his chin which makes his breath hitch. “I didn’t realize this was a competition, but if you say something like that, you just make me want to prove you wrong.”

Before he can respond, the shrill ringing of a cell phone interrupts, startling the two of you. At once, both of you turn toward the source of the sound. There you see his fur-lined, hooded jacket hanging on one of your bed posts. Well, that explains where his jacket went.

It’s only because the TV is on that you’re able to see the article of clothing thanks to the light it provides. Since you can’t hear what’s playing, you figure that Sans put in on mute some time before he went downstairs.

You raise an eyebrow at Sans when he doesn’t even attempt to get his phone. Sure, he’s probably too lazy to get up, but he could always use his magic to get it. “You gonna get that? What if it’s Papyrus?”

The skeleton scowls at his jacket as if it just insulted him. After a few seconds, he just shrugs his shoulders. “i doubt it’s anythin’ important. i’ll call him back later if it’s him. besides, i got somethin’ else i’d much rather do than answer a call.”

When you see his suggestive smirk, you roll your eyes in amusement. Not long afterwards, the phone stops ringing, so whoever it was must’ve given up. 

Now that you know where his jacket is, you can’t help but question him about it. “I was surprised to find you not wearing your jacket. You’re always wearing that thing. You even fall asleep in it sometimes. Did you go to bed before I got home?”

For some reason, a dark blush covers his cheekbones as Sans suddenly averts his eye-lights. You tilt your head curiously. Now, what could that be about? Is he embarrassed that you found out he was sleeping in your bed? You don’t know why he would be since you’ve never seen him use the guest bedroom.

“Okay, what’s up? You can’t make a cute face like that and not explain yourself. Come on, what’s got you so flustered?”

You have to prod him for several minutes before he finally gives in. Sans can be incredibly stubborn sometimes. Thankfully, a few well-placed kisses did the trick. 

He sighs in defeat all the while looking at anything but you. “while i like my jacket, it ain’t exactly the best smellin’ right now. it’s been awhile since it last got washed. i can’t really enjoy sleepin’ in here if i’m wearin’ it.”

When your brows furrow in confusion, Sans’ blush darkens before he continues. “even though it’s been a week since you last slept in here,your bed still smells like ya. i sleep better when i’m with ya. since i couldn’t have you this past week, i settled for the next best thing. damn, i didn’t realize how creepy that sounded ‘til i actually said it out-loud.”

Your heart swells with affection at his words. Before he can react, you crash your mouth against his. He takes a sharp breath from surprise, and you use that opening to slide your tongue past his teeth. You don’t give him any time to respond as you quickly move to ravish his mouth.

His grip is so tight it’s just shy of painful as he pulls you closer. You work to drag out as many pleased moans as you can by stroking his ribs and his neck all the while tangling your tongue with his.

It’s only because of your desperate need to breathe that you finally pull away. However, you don’t let your lips move more than a few inches from his teeth. 

Both of you are panting heavily now as you watch each other with hooded eyes. Then, you give him a sweet smile that makes his breath hitch. “It’s not creepy. To be honest, I find it really sweet that you missed me that much. I missed you like crazy while I was gone, and I was curious if you felt the same way or if I was just being over-dramatic. I’m glad that we feel the same way. That makes me really happy.”

His expression softens at your words. Sans uses the hand in your hair to tug you closer and remove the distance between your mouths. 

It’s only a chaste kiss, yet it feels like so much more. There’s a special gentleness in the kiss that makes you clutch him tighter in response. It’s amazing how much can be conveyed with just a simple kiss. With only that, you can tell just how much the skeleton cares about you.

After he ends the kiss, a fond grin forms on his face which makes your heart skip a beat. “damn, if i knew i’d get that kind of reaction, i woulda told ya sooner, sweetheart. i wouldn’t’ve tried to _cover_ it up.”

Giggling, you remove your hand from his rib cage so that you can wrap both of your arms around his neck. Sans raises a brow ridge when your smile turns mischievous. “There’s actually another surprise I have for you besides me coming home early. Wanna hear what it is?”

He chuckles in amusement. “sure thing, sweetheart. i’m all _ears_.”

Your grin grows as you lean close to affectionately nuzzle his neck. Then, you lower your voice to a seductive whisper. “I actually have the rest of this week off from work since I didn’t know for sure when one of my cousins would arrive. Now, if only there was someone to keep me company during all the free time that I’ll have.”

When you pull back, you see the large, wolfish grin on his face. You shiver when he runs a hand down your spine after pulling you closer. His eye-lights somehow appear to grow brighter as his face moves closer to yours. “what do ya know? my schedule is completely free this week. what are the chances?”

Your eyes fall half-mast as your faces continue to grow closer. “Pretty good if you ask me. Looks like the odds really are in my favor today.”

With that, Sans closes the remaining distance and captures your lips in a kiss that’s sure to be followed by many more. Now, you have several days that you can spend with your boyfriend, and you get to keep him all to yourself. You can’t think of a better way to spend the rest of your week.

While it didn’t go as you had originally planned, this is definitely the best Valentine’s Day you’ve ever had. You can’t wait for the next one.

**Author's Note:**

> I feel like I should apologize to y'all for the lack of plot in this lol Like, my main goal here was to just basically shower Sans in love and affection cause the guy could definitely use some. Besides, isn't that the point of Valentine's Day themed fanfic? Getting to kiss the person in the fic as much as you want? XD
> 
> Looking back at these two oneshots, I noticed they both end the same way, but I couldn't really think of different endings. Besides, it's not like y'all really wanted the kissing to end, right? ;)


End file.
